1. Field of the Invention
The present invention relates to an electrode structure of a wiring board that is connected to a connector; more particularly, to a connection terminal structure of a wiring board that enables prevention of occurrence of faulty insert connections to a connector and an optical disk drive using the structure.
2. Description of the Related Art
With recent functional advances in and miniaturization of electronic devices, electronic circuits arranged in the electronic devices also become further miniaturized and packaged at higher densities, as a result of which faulty connections attributable to a decrease in pitch between connectors of an electronic circuit component and connection terminals of a wiring board electrode raise a problem. For this reason, there is utilized a so-called staggered wiring technique for alternately displacing horizontally-arranged electrodes such that one electrode becomes in advance or behind an adjacent electrode, thereby assuring an area of a connection section and reduce electrical resistance. An example technique for enabling superior electrical conduction by reducing electrical resistance of a connection section between such an electrode and a connector terminal and making stable a connection between a wiring pattern and an electronic component is JPH04-15872(U).
In order to cause a device, such as an optical disk drive, to properly operate, a connection between a wiring board and a connector must be made stable at all times. In short, if the reliability of a connection between a wiring board and a connector becomes low for reasons of unfinished insertion or inclined insertion, the device will not become able to operate properly. A document (JP61-74971(U)) describes, as means for solving the problem, a technique for monitoring a state of disconnection between a wiring board and a connector, by making two specific connection terminals on the wiring board shorter than the other connection terminals and short-circuiting the two connection terminals.
However, according to the technique, it is possible to detect unfinished insertion of the connector to the wiring board but impossible to detect incomplete connection, such as inclined insertion (FIG. 2). Moreover, according to the technique disclosed in FIG. 3, it is possible to detect a state of inclined insertion. However, the connection terminals at both ends are short-circuited, and hence wiring becomes complicate. Further, although the wiring board and the connector are found to be in a state of unfinished insertion, it is impossible to determine whether the wiring board is upwardly inclined, downwardly inclined, or merely deficient in insertion without inclination. Hence, appropriate processing cannot be performed to assure a state of normal connection during the course of manufacture. In particular, a problem arises in a compact optical drive unit, such as a small-diameter drive unit.